CVE-2024-6387 | Openssh: regresshion - race condition in ssh allows rce/dos

Exp

A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate within a set time period.

Published: 2024-07-01 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-6387 is rated High Exploit Risk (82.6/100): CVSS High severity, with high exploitation likelihood (EPSS 63.83%, 98th percentile). 10 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2024-6387

EDB-ID Source Kind Published Link
52269 exploit_db edb 2025-04-22 Exploit-DB ↗
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Exploit prediction scoring system (EPSS) score for CVE-2024-6387

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-01 63.05% 63.83% +0.79%
2 2026-05-30 63.83% 63.05% -0.79%
3 2026-05-29 — 63.83% —

Full EPSS history (139 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-6387

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]

Weakness enumeration for CVE-2024-6387

GitHub Security Advisory for CVE-2024-6387

GHSA-2x8c-95vh-gfv4 · Severity: high — A signal handler race condition was found in OpenSSH's server (sshd), where a client does not...

OS Trackers for CVE-2024-6387

vendor priority summary link
alpine — CVE-2024-6387: 1 source package rows (openssh); 10 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 3. https://security.alpinelinux.org/vuln/CVE-2024-6387
debian unimportant CVE-2024-6387 unimportant priority: Debian including 1 source packages (openssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-6387
gentoo high CVE-2024-6387: 1 GLSA(s) (202407-09), 1 atom(s) (net-misc/openssh); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-6387
redhat high — https://access.redhat.com/security/cve/CVE-2024-6387
suse high CVE-2024-6387 severity important: SUSE including 312 source package names (15.7.20.5.1:openssh-9.6p1-150600.6.3.1, 15.7.20.5.1:openssh-clients-9.6p1-150600.6.3.1, …), 1140 product×package rows across 197 product lines (Container suse/git, Container suse/hpc/warewulf4-x86_64/sle-hpc-node, … (197 product lines)): Fixed 625, Known Not Affected 284, Known Affected 231. https://www.suse.com/security/cve/CVE-2024-6387/
ubuntu high CVE-2024-6387 high priority: Ubuntu including 2 source packages (openssh, openssh-ssh1), 14 status rows across 8 suites (bionic, focal, jammy, mantic, noble, trusty, upstream, xenial): not-affected 9, released 4, ignored 1. https://ubuntu.com/security/CVE-2024-6387

Affected software / configurations for CVE-2024-6387

Vendor Product Version Raw CPE
sonicwall sma_6200_firmware — cpe:2.3:o:sonicwall:sma_6200_firmware:-:*:*:*:*:*:*:*
sonicwall sma_7200_firmware — cpe:2.3:o:sonicwall:sma_7200_firmware:-:*:*:*:*:*:*:*
arista eos >= 4.32.0, <= 4.32.1f cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*
canonical ubuntu_linux 23.10 cpe:2.3:o:canonical:ubuntu_linux:23.10:*:*:*:*:*:*:*
canonical ubuntu_linux 24.04 cpe:2.3:o:canonical:ubuntu_linux:24.04:*:*:*:lts:*:*:*
almalinux almalinux 9.0 cpe:2.3:o:almalinux:almalinux:9.0:-:*:*:*:*:*:*
sonicwall sma_6210_firmware — cpe:2.3:o:sonicwall:sma_6210_firmware:-:*:*:*:*:*:*:*
sonicwall sma_7210_firmware — cpe:2.3:o:sonicwall:sma_7210_firmware:-:*:*:*:*:*:*:*
sonicwall sma_8200v_firmware — cpe:2.3:o:sonicwall:sma_8200v_firmware:-:*:*:*:*:*:*:*
sonicwall sra_ex_7000_firmware — cpe:2.3:o:sonicwall:sra_ex_7000_firmware:-:*:*:*:*:*:*:*
netapp a1k_firmware — cpe:2.3:o:netapp:a1k_firmware:-:*:*:*:*:*:*:*
netapp a70_firmware — cpe:2.3:o:netapp:a70_firmware:-:*:*:*:*:*:*:*
netapp a90_firmware — cpe:2.3:o:netapp:a90_firmware:-:*:*:*:*:*:*:*
netapp a700s_firmware — cpe:2.3:o:netapp:a700s_firmware:-:*:*:*:*:*:*:*
netapp 8300_firmware — cpe:2.3:o:netapp:8300_firmware:-:*:*:*:*:*:*:*
netapp 8700_firmware — cpe:2.3:o:netapp:8700_firmware:-:*:*:*:*:*:*:*
netapp a400_firmware — cpe:2.3:o:netapp:a400_firmware:-:*:*:*:*:*:*:*
netapp c400_firmware — cpe:2.3:o:netapp:c400_firmware:-:*:*:*:*:*:*:*
netapp a250_firmware — cpe:2.3:o:netapp:a250_firmware:-:*:*:*:*:*:*:*
netapp 500f_firmware — cpe:2.3:o:netapp:500f_firmware:-:*:*:*:*:*:*:*
netapp c250_firmware — cpe:2.3:o:netapp:c250_firmware:-:*:*:*:*:*:*:*
netapp a800_firmware — cpe:2.3:o:netapp:a800_firmware:-:*:*:*:*:*:*:*
netapp c800_firmware — cpe:2.3:o:netapp:c800_firmware:-:*:*:*:*:*:*:*
netapp a900_firmware — cpe:2.3:o:netapp:a900_firmware:-:*:*:*:*:*:*:*
netapp a9500_firmware — cpe:2.3:o:netapp:a9500_firmware:-:*:*:*:*:*:*:*
netapp c190_firmware — cpe:2.3:o:netapp:c190_firmware:-:*:*:*:*:*:*:*
netapp a150_firmware — cpe:2.3:o:netapp:a150_firmware:-:*:*:*:*:*:*:*
netapp a220_firmware — cpe:2.3:o:netapp:a220_firmware:-:*:*:*:*:*:*:*
netapp fas2720_firmware — cpe:2.3:o:netapp:fas2720_firmware:-:*:*:*:*:*:*:*
netapp fas2750_firmware — cpe:2.3:o:netapp:fas2750_firmware:-:*:*:*:*:*:*:*
netapp fas2820_firmware — cpe:2.3:o:netapp:fas2820_firmware:-:*:*:*:*:*:*:*
netapp bootstrap_os — cpe:2.3:o:netapp:bootstrap_os:-:*:*:*:*:*:*:*
apple macos >= 12.0, < 12.7.6 cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
apple macos >= 13.0, < 13.6.8 cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
apple macos >= 14.0, < 14.6 cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
openbsd openssh < 4.4 cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
openbsd openssh >= 8.6, <= 9.8 cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
openbsd openssh 4.4 cpe:2.3:a:openbsd:openssh:4.4:-:*:*:*:*:*:*
openbsd openssh 8.5 cpe:2.3:a:openbsd:openssh:8.5:p1:*:*:*:*:*:*
openbsd openssh 8.6 cpe:2.3:a:openbsd:openssh:8.6:-:*:*:*:*:*:*
redhat openshift_container_platform 4.0 cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux_eus 9.4 cpe:2.3:o:redhat:enterprise_linux_eus:9.4:*:*:*:*:*:*:*
redhat enterprise_linux_for_arm_64 9.0_aarch64 cpe:2.3:o:redhat:enterprise_linux_for_arm_64:9.0_aarch64:*:*:*:*:*:*:*
redhat enterprise_linux_for_arm_64_eus 9.4_aarch64 cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:9.4_aarch64:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems 9.0_s390x cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:9.0_s390x:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_eus 9.4_s390x cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:9.4_s390x:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian 9.0_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:9.0_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian_eus 9.4_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:9.4_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 9.4 cpe:2.3:o:redhat:enterprise_linux_server_aus:9.4:*:*:*:*:*:*:*
suse linux_enterprise_micro 6.0 cpe:2.3:o:suse:linux_enterprise_micro:6.0:*:*:*:*:*:*:*
debian debian_linux 12.0 cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*
canonical ubuntu_linux 22.04 cpe:2.3:o:canonical:ubuntu_linux:22.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 22.10 cpe:2.3:o:canonical:ubuntu_linux:22.10:*:*:*:-:*:*:*
canonical ubuntu_linux 23.04 cpe:2.3:o:canonical:ubuntu_linux:23.04:*:*:*:lts:*:*:*
amazon amazon_linux 2023.0 cpe:2.3:o:amazon:amazon_linux:2023.0:*:*:*:*:*:*:*
netapp active_iq_unified_manager — cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
netapp e-series_santricity_os_controller >= 11.0.0, <= 11.70.2 cpe:2.3:a:netapp:e-series_santricity_os_controller:*:*:*:*:*:*:*:*
netapp ontap 9 cpe:2.3:a:netapp:ontap:9:*:*:*:*:*:*:*
netapp ontap_select_deploy_administration_utility — cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*
netapp ontap_tools 9 cpe:2.3:a:netapp:ontap_tools:9:*:*:*:*:vmware_vsphere:*:*
netapp ontap_tools 10 cpe:2.3:a:netapp:ontap_tools:10:*:*:*:*:vmware_vsphere:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:-:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p1:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p10:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p11:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p2:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p3:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p4:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p5:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p6:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p7:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p8:*:*:*:*:*:*
freebsd freebsd 13.2 cpe:2.3:o:freebsd:freebsd:13.2:p9:*:*:*:*:*:*
freebsd freebsd 13.3 cpe:2.3:o:freebsd:freebsd:13.3:-:*:*:*:*:*:*
freebsd freebsd 13.3 cpe:2.3:o:freebsd:freebsd:13.3:p1:*:*:*:*:*:*
freebsd freebsd 13.3 cpe:2.3:o:freebsd:freebsd:13.3:p2:*:*:*:*:*:*
freebsd freebsd 13.3 cpe:2.3:o:freebsd:freebsd:13.3:p3:*:*:*:*:*:*
freebsd freebsd 14.0 cpe:2.3:o:freebsd:freebsd:14.0:-:*:*:*:*:*:*
freebsd freebsd 14.0 cpe:2.3:o:freebsd:freebsd:14.0:beta5:*:*:*:*:*:*

References for CVE-2024-6387

URL Tags
https://access.redhat.com/errata/RHSA-2024:4312 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4340 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4389 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4469 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4474 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4479 Third Party Advisory
https://access.redhat.com/errata/RHSA-2024:4484 Third Party Advisory
https://access.redhat.com/security/cve/CVE-2024-6387 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2294604 Third Party Advisory
https://santandersecurityresearch.github.io/blog/sshing_the_masses.html Exploit Third Party Advisory
https://www.openssh.com/txt/release-9.8 Release Notes Third Party Advisory
https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt Exploit Third Party Advisory
http://seclists.org/fulldisclosure/2024/Jul/18 Mailing List
http://seclists.org/fulldisclosure/2024/Jul/19 Mailing List
http://seclists.org/fulldisclosure/2024/Jul/20 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/01/12 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/01/13 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/02/1 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/03/1 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/03/11 Exploit Mailing List
http://www.openwall.com/lists/oss-security/2024/07/03/2 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/03/3 Mailing List Patch
http://www.openwall.com/lists/oss-security/2024/07/03/4 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/03/5 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/04/1 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/04/2 Exploit Mailing List
http://www.openwall.com/lists/oss-security/2024/07/08/2 Exploit Mailing List
http://www.openwall.com/lists/oss-security/2024/07/08/3 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/09/2 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/09/5 Exploit Mailing List
http://www.openwall.com/lists/oss-security/2024/07/10/1 Exploit Mailing List
http://www.openwall.com/lists/oss-security/2024/07/10/2 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/10/3 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/10/4 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/10/6 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/11/1 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/11/3 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/23/4 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/23/6 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/28/2 Mailing List
http://www.openwall.com/lists/oss-security/2024/07/28/3 Mailing List
https://archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openssh-98p1/ Third Party Advisory
https://arstechnica.com/security/2024/07/regresshion-vulnerability-in-openssh-gives-attackers-root-on-linux/ Press/Media Coverage Third Party Advisory
https://blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthenticated-code-execution-vulnerability-in-openssh-server Press/Media Coverage Third Party Advisory
https://explore.alas.aws.amazon.com/CVE-2024-6387.html Third Party Advisory
https://forum.vmssoftware.com/viewtopic.php?f=8&t=9132 Issue Tracking
https://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2024-002.txt.asc Release Notes
https://github.com/AlmaLinux/updates/issues/629 Issue Tracking
https://github.com/Azure/AKS/issues/4379 Issue Tracking
https://github.com/PowerShell/Win32-OpenSSH/discussions/2248 Issue Tracking
https://github.com/PowerShell/Win32-OpenSSH/issues/2249 Issue Tracking
https://github.com/microsoft/azurelinux/issues/9555 Issue Tracking
https://github.com/openela-main/openssh/commit/e1f438970e5a337a17070a637c1b9e19697cad09 Patch
https://github.com/oracle/oracle-linux/issues/149 Issue Tracking
https://github.com/rapier1/hpn-ssh/issues/87 Issue Tracking
https://github.com/zgzhang/cve-2024-6387-poc Third Party Advisory
https://lists.almalinux.org/archives/list/[email protected]/thread/23BF5BMGFVEVUI2WNVAGMLKT557EU7VY/ Third Party Advisory
https://lists.mindrot.org/pipermail/openssh-unix-announce/2024-July/000158.html Mailing List Release Notes
https://lists.mindrot.org/pipermail/openssh-unix-dev/2024-July/041431.html Mailing List Patch
https://news.ycombinator.com/item?id=40843778 Issue Tracking Patch
https://packetstorm.news/files/id/190587/ Broken Link
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0010 Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2024-6387 Third Party Advisory
https://security.netapp.com/advisory/ntap-20240701-0001/ Third Party Advisory
https://sig-security.rocky.page/issues/CVE-2024-6387/ Third Party Advisory
https://stackdiary.com/openssh-race-condition-in-sshd-allows-remote-code-execution/ Press/Media Coverage Third Party Advisory
https://support.apple.com/kb/HT214118 Third Party Advisory
https://support.apple.com/kb/HT214119 Third Party Advisory
https://support.apple.com/kb/HT214120 Third Party Advisory
https://ubuntu.com/security/CVE-2024-6387 Third Party Advisory
https://ubuntu.com/security/notices/USN-6859-1 Third Party Advisory
https://www.akamai.com/blog/security-research/2024-openssh-vulnerability-regression-what-to-know-and-do Third Party Advisory
https://www.arista.com/en/support/advisories-notices/security-advisory/19904-security-advisory-0100 Third Party Advisory
https://www.exploit-db.com/exploits/52269 Exploit
https://www.freebsd.org/security/advisories/FreeBSD-SA-24:04.openssh.asc Third Party Advisory
https://www.splunk.com/en_us/blog/security/cve-2024-6387-regresshion-vulnerability.html Third Party Advisory
https://www.suse.com/security/cve/CVE-2024-6387.html Third Party Advisory
https://www.theregister.com/2024/07/01/regresshion_openssh/ Press/Media Coverage Third Party Advisory
https://www.vicarius.io/vsociety/posts/regresshion-an-openssh-regression-error-cve-2024-6387 Exploit Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
https://cert-portal.siemens.com/productcert/html/ssa-446545.html
cvelogic Threat Intelligence